Structural, electrophysiological and psychophysical studies on the relationship between the corneal nerves and epithelial cells will be carried out. These include: 1. The use of nerve extracts or transmitter substances in the denervated cornea to mimic the trophic effects of the nerve. 2. Examination of changes in ultrastructure of the denervated epithelium, especially during wound healing. 3. Determination whether the loss of corneal sensitivity produced by soft contact lens wear is of central or peripheral origin. 4. Study of action of nicotinic and muscarinic agents on the response of sensory units in the cornea.